This project was conceived to test the efficacy of genetically modified human CD8 CTL or CD4 cells to treat or resist HIV-1 infection in SCID mice transplanted with human peripheral blood mononuclear cells (hu-PBL-SCID mice). The general plan was to compare efficacy of HIV-specific CTL in patients to the results seen in hu-PBL-SCID mice. The advantage of the hu-PBL-SCID surrogate human model is that we can follow CTL distribution and half-life in tissues, and also calculate in vivo effector:infected target ratios, thus making it possible to define reasons for therapeutic failures and minimal conditions for significant antiviral activity.